powerpc/pseries: Don't panic when H_PROD fails during cpu-online.

If an online-attempt on a CPU which has been offlined using H_CEDE
with an appropriate cede latency hint fails, don't panic.

Instead print the error message and let the __cpu_up() code notify the
CPU Hotplug framework of the failure, which in turn can notify the
other subsystem through CPU_UP_CANCELED.
Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/pseries/smp.c

@@ -144,8 +144,8 @@ static void __devinit smp_pSeries_kick_cpu(int nr)
 		hcpuid = get_hard_smp_processor_id(nr);
 		rc = plpar_hcall_norets(H_PROD, hcpuid);
 		if (rc != H_SUCCESS)
-			panic("Error: Prod to wake up processor %d Ret= %ld\n",
-				nr, rc);
+			printk(KERN_ERR "Error: Prod to wake up processor %d\
+						Ret= %ld\n", nr, rc);
 	}
 }